It is much easier if you use GNU Automake instead of writing your own
Makefiles. If you do that you do not have to worry about finding and
gpgme-config script at all. GPGME
provides an extension to Automake that does all the work for you.
Check whether GPGME (at least version minimum-version, if given) exists on the host system. If it is found, execute action-if-found, otherwise do action-if-not-found, if given.
Additionally, the function defines
GPGME_CFLAGS to the flags
needed for compilation of the program to find the gpgme.h
header file, and
GPGME_LIBS to the linker flags needed to link
the program to the GPGME library. If the used helper script
does not match the target type you are building for a warning is
printed and the string
libgcrypt is appended to the variable
AM_PATH_GPGME_PTH checks for the version of GPGME
that can be used with GNU Pth, and defines
AM_PATH_GPGME_PTHREAD checks for the version of GPGME
that can be used with the native pthread implementation, and defines
version 1.8.0 this is no longer required to GPGME_PTHREAD as
GPGME itself is thread safe.
This macro searches for
gpgme-config along the PATH. If
you are cross-compiling, it is useful to set the environment variable
SYSROOT to the top directory of your target. The macro will
then first look for the helper program in the bin directory
below that top directory. An absolute directory name must be used for
SYSROOT. Finally, if the configure command line option
--with-gpgme-prefix is used, only its value is used for the top
directory below which the helper script is expected.
You can use the defined Autoconf variables like this in your Makefile.am:
AM_CPPFLAGS = $(GPGME_CFLAGS) LDADD = $(GPGME_LIBS)